Commit ccadc8a2 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm-delay: avoid duplicate logic 



This is small refactoring of dm-delay - we avoid duplicate logic in
flush_delayed_bios and flush_delayed_bios_fast and join these two
functions into one.

We also add cond_resched() to flush_delayed_bios because the list may have
unbounded number of entries.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 38cfff56

drivers/md/dm-delay.c

+21 −44
Original line number Diff line number Diff line
@@ -85,24 +85,40 @@ static void flush_bios(struct bio *bio) 
	}

}



static void flush_delayed_bios_fast(struct delay_c *dc, bool flush_all)

static void flush_delayed_bios(struct delay_c *dc, bool flush_all)

{

	struct dm_delay_info *delayed, *next;

	struct bio_list flush_bio_list;

	unsigned long next_expires = 0;

	bool start_timer = false;

	bio_list_init(&flush_bio_list);



	mutex_lock(&delayed_bios_lock);

	list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {

		cond_resched();

		if (flush_all || time_after_eq(jiffies, delayed->expires)) {

			struct bio *bio = dm_bio_from_per_bio_data(delayed,

						sizeof(struct dm_delay_info));

			list_del(&delayed->list);

			bio_list_add(&flush_bio_list, bio);

			delayed->class->ops--;

			continue;

		}



		if (!delay_is_fast(dc)) {

			if (!start_timer) {

				start_timer = true;

				next_expires = delayed->expires;

			} else {

				next_expires = min(next_expires, delayed->expires);

			}

		}

	}

	mutex_unlock(&delayed_bios_lock);



	if (start_timer)

		queue_timeout(dc, next_expires);



	flush_bios(bio_list_get(&flush_bio_list));

}
@@ -111,7 +127,7 @@ static int flush_worker_fn(void *data) 
	struct delay_c *dc = data;



	while (!kthread_should_stop()) {

		flush_delayed_bios_fast(dc, false);

		flush_delayed_bios(dc, false);

		mutex_lock(&delayed_bios_lock);

		if (unlikely(list_empty(&dc->delayed_bios))) {

			set_current_state(TASK_INTERRUPTIBLE);
@@ -126,47 +142,11 @@ static int flush_worker_fn(void *data) 
	return 0;

}



static void flush_delayed_bios(struct delay_c *dc, bool flush_all)

{

	struct dm_delay_info *delayed, *next;

	unsigned long next_expires = 0;

	unsigned long start_timer = 0;

	struct bio_list flush_bio_list;

	bio_list_init(&flush_bio_list);



	mutex_lock(&delayed_bios_lock);

	list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {

		if (flush_all || time_after_eq(jiffies, delayed->expires)) {

			struct bio *bio = dm_bio_from_per_bio_data(delayed,

						sizeof(struct dm_delay_info));

			list_del(&delayed->list);

			bio_list_add(&flush_bio_list, bio);

			delayed->class->ops--;

			continue;

		}



		if (!start_timer) {

			start_timer = 1;

			next_expires = delayed->expires;

		} else

			next_expires = min(next_expires, delayed->expires);

	}

	mutex_unlock(&delayed_bios_lock);



	if (start_timer)

		queue_timeout(dc, next_expires);



	flush_bios(bio_list_get(&flush_bio_list));

}



static void flush_expired_bios(struct work_struct *work)

{

	struct delay_c *dc;



	dc = container_of(work, struct delay_c, flush_expired_bios);

	if (delay_is_fast(dc))

		flush_delayed_bios_fast(dc, false);

	else

	flush_delayed_bios(dc, false);

}
@@ -354,13 +334,10 @@ static void delay_presuspend(struct dm_target *ti) 
	dc->may_delay = false;

	mutex_unlock(&delayed_bios_lock);



	if (delay_is_fast(dc)) {

		flush_delayed_bios_fast(dc, true);

	} else {

	if (!delay_is_fast(dc))

		del_timer_sync(&dc->delay_timer);

	flush_delayed_bios(dc, true);

}

}



static void delay_resume(struct dm_target *ti)

{